The broad objective of this research is to elucidate immune mechanims which accompany or cause hypersensitivity and inflammation in the gut. The effect of secretory antibody on IgE antibody production will be examined as a continuation of current studies on the effect of exposure to environmental antigens on secretory and IgE antibody responses in mice. Phosphoryl choline(PC)-binding IgA myeloma protein will be passively transferred to suckling neonates and their responses to the PC determinant measured by radioimmunoassay for isotype-specific serum antibody and by splenic focusing assay for precursors of antibody-forming cells. The role of IgE antibody in intestinal goblet cell mucin (GCM) relase will be studied in rats and mice passively sensitized with IgE monoclonal antibody: release is monitored after in vivo labeling of GCM with 35S. The effect of other antibody isotypes, either alone or in combination with IgE, will be tested. The role of mast cells will be assessed by using rats and mice infected with Nippostrongylus brasiliensis, by using mast cell-deficient W/Wv mice, and by measuring histamine released into the lumen of the gut. We will test the hypothesis that T lymphocytes regulate goblet cells in the gut. As expulsion of NIppostrongylus is T cell-dependent and is associated with goblet cell proliferation and GCM release, goblet cells will be monitored histologically and GCM relase will be examined in athymic nude mice. If the hypothesis is correct, goblet cells will increase in normal but not in nude mice and transfer of T cells into nude mice should restore the response. Adoptive transfer experiments with T cells from various sources, e.g., mesenteric lymph nodes, spleen, and cell populations depleted of T cells having various surface markers, e.g., Thy-1, Lyl.1, will be done. Similar experiments will be done in mice in which an intestinall inflammatory response is induced by a graft-vs-host reaction. There is speculation about gastrointestinal lallergy and the role of IgE, mast cells and goblet cells in immunity in the gut. The proposed analyses are designed to reveal some general principles about the role of these components in the physiology to reveal some general principles about the role of these components in the physiology and pathology of the gut.